Heretofore, an image reader apparatus for reading an image with an image sensor while emitting light from a light source and outputting an image signal has been utilized as an apparatus for reading an object image such as a printed matter or a photograph (an image on a document) (See, e.g., Japanese laid-open patent publication No. 2004-126721 (Patent Document 1)).
For a light source of such a reader apparatus, LEDs, which consume low electric power and are highly responsive, have heavily been used. Furthermore, for an image sensor, one-dimensional CCD sensors in which a plurality of light-receiving elements are arrayed in one direction have heavily been used. As shown in FIG. 6, a one-dimensional CCD sensor, which may be referred to as “CCD” in context, includes a light-receiving part 33 for storing charges corresponding to the quantity of incident light in respective light-receiving pixels 32, a horizontal transfer part 34 for transferring the charges stored in the light-receiving part 33 in the horizontal direction, an output part 35 for converting the charges transferred from the horizontal transfer part 34 into image signals and outputting the image signals, and the like.